# SUSY 2015, 23rd International Conference on Supersymmetry and Unification of Fundamental Interactions

23-29 August 2015
Lake Tahoe
US/Pacific timezone

## Partially Natural Two Higgs Doublet Models

24 Aug 2015, 16:30
20m
Lake ()

### Lake

Higgs Theory and Experiment

### Speaker

Howard Haber (University of California,Santa Cruz (US))

### Description

It is possible that the electroweak scale is low in part due to selection effects, i.e., fine-tuning of the microscopic parameters. The experimental discovery of new light fundamental scalars other than the Standard Model Higgs boson would cast doubt on this theory, since generically such states imply parametrically worse fine-tuning with no compelling connection to selection effects. However, discovering new scalars does not guarantee that the electroweak scale is natural. We discuss counterexamples in which the Higgs boson is light because of fine-tuning and a second scalar doublet is light because of simple discrete symmetries. Such models typically require new vector-like fermions and can have a rich electroweak vacuum structure. The mechanism we discuss cannot be easily applied to protect a small $m_A$ in split or high-scale SUSY-breaking scenarios of the MSSM due to an incompatibility between the discrete symmetries and holomorphy.

### Primary author

Howard Haber (University of California,Santa Cruz (US))

### Co-authors

Joshua Ruderman (Princeton University)